1. Field of the Invention
This invention generally relates to compositions for preparing formulated arthropod cadavers containing biological organisms having pesticidal and/or antimicrobial activity, compositions containing formulated arthropod cadavers, and a method for preparing and using formulated arthropod cadavers.
2. Description of the Related Art
Control of pest and/or microbial infestations and the direct loss caused by infestations are costly. Myriad approaches have been pursued to control pests. It is well known to encapsulate fungi, bacteria, and nematodes in alginate or starch matrices. Wheat gluten also has been employed for encapsulation. Ordinarily, the encapsulated product is in the form of granules (i.e., pellets or particulates) that are dispersed or sprayed directly upon or in the locus of an area infested with weeds, insects, diseases, and nematodes that are harmful to plants and agricultural crops. The purpose of the biocontrol agent is to control (e.g., reduce the population or growth, or possibly eliminate) the target pest. One of the problems associated with such encapsulated biocontrol agents is that the granules tend to dry out too quickly, which is harmful to the agent since moisture is necessary for their survival.
Entomopathogenic nematodes are just one example of a biocontrol agent which can be formulated into a carrier to control pests. Entomopathogenic nematodes in the genera Steinernema and Heterorhabditis are obligate parasites of insects (Kaya and Gaugler, Entomopathogenic nematodes, Annu. Rev. Entomol., Volume 38, 181-206, 1993). Entomopathogenic nematodes are biological control agents that generally infect their host by entering natural openings in the host. Heterorhabditids also have the ability to enter certain hosts through the cuticle using a tooth. After entering a host, symbiotic bacteria are released, the nematodes molt and reproduce, and after 1-3 generations, dauer stage juveniles emerge. The dauer juvenile stage is the only stage that is capable of surviving and infecting new hosts in the natural environment. Infective juveniles enter the host and release symbiotic bacteria which aid in (a) killing the host, (b) providing nutrients to the nematodes, and (c) releasing antibiotics, which prevent invasion by other microbes; the bacteria, however cannot survive outside of the host in a natural environment (e.g. soil) without the nematode (Poinar, Biology and taxonomy of Steinernematidae and Heterorhabditidae, In: Entomopathogenic Nematodes in Biological Control, R. Gaugler and H. K. Kaya, Eds., 23-62, 1990, CRC Press, Boca Raton, Fla.). The number of nematodes produced per insect varies among nematode species, and within species in different hosts. Heterorhabditis bacteriophora Poinar, for example, can produce over 500,000 infective juveniles per Galleria mellonella (L.) larva.
Entomopathogenic nematodes are important biological control agents for a variety of economically important pests in agricultural and urban environments (Grewal and Georgis, Entomopathogenic nematodes, IN: xe2x80x9cMethods in Biotechnologyxe2x80x9d, Volume 5, Biopesticides: Use and Delivery, F. R. Hall and J. J. Menn, Eds., 271-299, 1998, Totowa, N. J., Humana Press, Inc.; Kaya and Gaugler, 1993, supra). The nematodes can be mass-produced using in vivo and in vitro methods (Friedman, Commercial production and development, In: xe2x80x9cEntomopathogenic Nematodes in Biological Control, R. Gaugler and H. K. Kaya, Eds., 153-172, 1990 Boca Raton, Fla., CRC Press). Entomopathogenic nematodes are commercially applied as infective juveniles in aqueous suspensions using various irrigation systems, sprayers, or injection techniques (Georgis, Formulation and application technology, IN: xe2x80x9cEntomopathogenic Nematodes in Biological Control, supra, 173-194, 1990; Koppenhofer, Nematodes, IN: xe2x80x9cField Manual of Techniques in Invertebrate Pathologyxe2x80x9d, L. A. Lacey and H. K. Kaya, Eds., 283-301, 2000, Kluwer Academic Publishers, Dordrecht).
Research indicates that entomopathogenic nematodes may also be applied in infected cadavers [(Creighton and Fassuliotis, Heterorhabditis sp. (Nematoda: Heterorhabditidae): A nematode parasite isolated from the banded cucumber beetle Diabrotica balteata, J. Nematology, Volume 17, 150-153, 1985; Jansson et al., Field efficacy and persistence of entomopathogenic nematodes (Rhabditida: Steinernematidae, Heterorhabditidae) for control of sweet potato weevil (Coleoptera: Apionidae) in Southern Florida, J. Econ. Entomology, Volume 86, 1055-1063, 1993)]. In this approach, nematode-infected cadavers are disseminated and pest suppression is subsequently achieved by the progeny infective juveniles that exit the cadavers. Laboratory studies indicate that nematode application in infected-hosts may be superior to application in aqueous suspension (Shapiro and Glazer, Comparison of entomopathogenic nematode dispersal from infected hosts versus aqueous suspension, Environ. Entomol., Volume 25, 1455-1461, 1996; Shapiro and Lewis, Comparison of entomopathogenic nematode infectivity from infected hosts versus aqueous suspension, Environ. Entomol., Volume 28, 907-911, 1999). However, commercialization of nematode-infected cadavers has been prevented due to problems in storage and application (Koppenhofer, 2000, supra). Nematode-infected hosts stick together or rupture during transport and/or application, which results in reduced efficacy. Formulation of nematode-infected cadavers can overcome these problems by providing shelf-life, stability of product from transport to application, and ease of handling (Georgis et al., Formulation of entomopathogenic nematodes, In:xe2x80x9cBiorational Pest Control Agents: Formulation and Delivery, F. R. Hall and J. W. Barry, Eds., 197-205, 1995, Washington, D.C.: American Chemical Society). Entomopathogenic nematodes have been formulated for commercial application in various carriers including clay, activated charcoal, sponge, vermiculite, peat, alginate gels, and water dispersible granules (Georgis, 1990, supra; Georgis et al., 1995, supra). Shelf-life, in most formulations, is enhanced by reducing nematode metabolism through partial desiccation, and, or , storage at low temperatures such as, for example, about 4-15xc2x0 C. (Georgis et al., 1995, supra). Desiccation is a common method used during entomopathogenic nematode formulation to increase shelf-life by decreasing nematode metabolism. The anhydrobiotic potential of entomopathogenic nematodes, however is limited. If the rate of desiccation is inappropriate, high nematode mortality occurs. For example, 100% mortality was reported in S. carpocapsae (Weiser) after three days exposure to 60% relative humidity or one day exposure to 0 or 40% relative humidity (Womersley, Factors affecting physiological fitness and modes of survival employed by dauer juveniles and their relationship to pathogenicity; IN: xe2x80x9cNematodes for the Biological Control fo Insectsxe2x80x9d; R. A. Bedding et al., eds; 79-88, CSIRO Press, East Melbourne, Australis; 1993). Heterorhabditis bacteriophora has been found to be less desiccation tolerant than S. carpocapsae (Glazer and Navon, J. Econ. Entomology, Volume 83, 1795-1800, 1990). Koppenhofer (2000, supra) reported that entomopathogenic nematodes can survive dry conditions for extended periods if they remain inside a host cadaver.
Various formulations for entomopathogenic organisms are known, however there remains a need in the art for formulations which prolong shelf-life of formulated entomopathogens while at least maintaining infectivity and reproduction levels for effective biological control. The present invention, as described below, is different from related art formulations.
It is therefore an object of the present invention to provide a formulated arthropod cadaver containing a pesticidal and/or antimicrobial biological organism as a biocontrol agent in which at least viability and/or reproductive capacity of the biological organism in the formulated arthropod cadavers is improved over that of non-formulated arthropod cadavers.
Another object of the present invention to provide a formulated arthropod cadaver containing a pesticidal and/or antimicrobial biological organism as a biocontrol agent in which at least infectivity of the biological organism in the formulated arthropod cadavers is equal or greater than that of a non-formulated biocontrol agent-containing arthropod cadaver.
A still further object of the present invention is to provide a formulated arthropod cadaver containing a pesticidal and/or antimicrobial biological organism as a biocontrol agent in which at least storability of the biological agent in the formulated arthropod cadavers is improved over that of a non-formulated biocontrol agent-infected cadaver.
Another object of the present invention is to provide a method for formulating pesticidal and/or antimicrobial biological organisms in arthropod cadavers as a biological control agent in which viability and/or reproductive capacity is improved over that of non-formulated arthropod cadavers containing pesticidal and/or antimicrobial biological organisms.
A further object of the present invention is to provide a method for formulating pesticidal and/or antimicrobial biological organism-containing arthropod cadavers as a biocontrol agent in which infectivity of the biological organism is equal to or greater than that of non-formulated biological organism-containing arthropod cadavers.
A still further object of the present invention is to provide a method for formulating pesticidal and/or antimicrobial biological organism-containing arthropod cadavers as a biocontrol agent in which storability is improved over that of non-formulated cadavers.
A further object of the present invention is to provide a biocontrol agent that includes formulated pesticidal and/or antimicrobial biological organism-containing arthropod cadavers.
Further objects and advantages of the invention will become apparent from the following description.